Fat Mass Centile Charts for Brazilian Children and Adolescents and the Identification of the Roles of Socioeconomic Status and Physical Fitness on Fat Mass Development.

This paper presents fat mass centile charts for Brazilian youth and investigates the roles of socioeconomic status and physical fitness (PF) on fat mass (FM) development. Two northeast Brazilian samples were used: a cross-sectional sample of 3659 (1921 girls) aged 8 to 16 years and a mixed-longitudinal series of cohorts (8-10, 10-12, 12-14, 14-16 years) with 250 boys and 250 girls. A measure of somatic maturity was used as a marker of biological maturation; PF comprised agility, explosive and static strength, and aerobic capacity. Socioeconomic status was based on school attended; public or private. Slaughter's anthropometric equations were used to estimate FM. Percentile charts was constructed using the LMS method. HLM (Hierarchical Linear Model) 7 software modeled FM changes, identifying inter-individual differences and their covariates. Girls and boys had different FM percentile values at each age; FM increased nonlinearly in both girls and boys. Higher PF levels reduced FM changes across time in both sexes. Sex-specific non-linear FM references were provided representing important tools for nutritionists, pediatriciann and educators. Physical fitness levels were found to act as a protective factor in FM increases. As such, we emphasize PF importance as a putative health marker and highlight the need for its systematic development across the school years.